CDQ furnace air inlet closed circuit system

Abstract

The present invention provides a closed-circuit air inlet system for a dry quenching furnace, wherein the furnace body is divided into a pre-storage section and a cooling section from top to bottom, and an upper annular air duct is formed in the furnace body at positions corresponding to the pre-storage section and the cooling section. A coke discharge system and a circulating air inlet system are arranged at the bottom of the dry quenching furnace, and the upper air chamber and the lower air chamber of the circulating air inlet system are connected to the furnace body, and a flap valve is arranged at the outlet of the circulating fan, and the flap valve is respectively connected to the upper air chamber and the lower air chamber through the upper air chamber connecting pipe and the lower air chamber connecting pipe, and the circulating air flow in the furnace body enters the cooling section through the upper air chamber and the lower air chamber and flows back to the circulating fan through the upper annular air duct, the primary dust removal unit, and the boiler; a flat gate is arranged in the coke discharge system, and a circulating air inlet system is provided with a circulating air cut-off valve between the circulating fan and the flap valve; and a discharge cut-off valve is arranged below the flat gate. The dry quenching furnace is provided with an air inlet closed-circuit system to form a sealed air path circulation system, which can effectively prevent the leakage of coke powder, and at the same time, prevent the leakage of high-temperature coke powder from burning the staff, and has high safety.

Description

Technical Field

[0001] The invention relates to the technical field of coking dry quenching production process and equipment manufacturing, in particular to a closed-circuit air inlet system for a dry quenching coke oven with a circulating air inlet system and a coke discharge system. Background Art

[0002] The coke drum with 1000℃ red coke enters the dry quenching furnace through the elevator. In the cooling section of the dry quenching furnace, the coke flows downward, and the inert circulating gas is sent into the upper and lower air chambers and the central air duct in the cross hood through the circulating fan. The inert gas flows upward, and the coke flows downward. The coke is cooled by heat exchange with the circulating gas. The coke discharged from the dry quenching furnace can be cooled to below 200℃. The inert circulating gas exchanges heat with the coke in the cooling section of the dry quenching furnace in countercurrent, and enters the dry quenching boiler after heating to 900-960℃. Since a small amount of air will leak into the negative pressure section of the gas circulation system, O2 will react with the coke through the red coke layer to generate CO2, and CO2 will be reduced to CO in the high temperature area of ​​the coke layer. With the increase of the number of cycles, the CO concentration in the circulating gas becomes higher and higher. In addition, the residual volatile matter of coke is always precipitating, and the H2, CO, CH4, etc. generated by the pyrolysis of coke are also flammable and explosive components. Therefore, during the dry quenching operation, the concentration of combustible components in the circulating gas must be controlled below the explosion limit. Generally, there are two measures to control it. First, continuously add an appropriate amount of industrial N2 to the gas circulation system to dilute the combustible components in the circulating gas, and then release the corresponding amount of circulating gas; second, continuously introduce an appropriate amount of air into the circulating gas drawn out at a temperature of 900-960°C to burn the increased combustible components, and then release the corresponding amount of circulating gas after cooling by the boiler. Both methods can be feedback-regulated by the concentration of H2 and CO in the circulating gas measured by the automatic online gas analyzer installed on the circulating gas pipeline.

[0003] like Figures 1 to 5 As shown, currently all the circulating gas of the CDQ furnace directly enters a flap valve through a circulating fan, and two sets of regulating flaps are provided in the flap valve to enter the upper air chamber and the lower air chamber of the blast device respectively. The upper air chamber enters the CDQ furnace through the gap between the double-layer cone buckets, and enters the lower air chamber all the way to the central air chamber. The outlet of the CDQ furnace is below the blast device. The coke discharge system is composed of a flat gate, a transition chute, a vibrating feeder, a rotary sealing valve, a double-branch chute and a belt at the CDQ furnace outlet.

[0004] The flap valve is usually used to adjust the air volume and cannot be used as a cut-off function. The flat gate only cuts off the coke at the dry quenching furnace outlet. The coke discharge system is directly connected to the outside to prevent coke discharge when it is necessary to stop coke discharge. Since the flat gate cuts off coke particles, the gate cannot cut off the gas function.

[0005] Equipment damage in the CDQ system requires non-stop maintenance, such as boiler tube bursts, etc., which requires stopping the circulating fan and then performing online repairs for one or several days. Only the furnace needs to be shut down for maintenance. Currently, the flap valve after the circulating fan is closed and the flat gate at the CDQ grate outlet can only be closed. Since the air leakage is very serious after the flap valve and the flat gate are closed, one: the air enters the upper and lower air chambers into the CDQ furnace through the circulating fan, and the other: the air directly enters the CDQ furnace from the flat gate through the coke exhaust system and the blast device. For a long time, the coke in the CDQ furnace will reignite. In severe cases, the cross hood will be burned and collapsed, and the cross channel will be burned, making the entire CDQ furnace unusable and requiring shutdown for overhaul.

[0006] In addition, when the rotary sealing valve of the CDQ furnace coke discharge system is stuck and needs emergency repair, the online repair is only carried out after reducing the fan air volume and air pressure. Since the flat gate cannot be closed and cut off, it is very dangerous for the maintenance personnel to operate (the largest accident occurred in a domestic steel enterprise during maintenance with two deaths). Close the discharge shut-off valve in the coke discharge system to prevent the inert gas in the CDQ furnace from being discharged downward and start the safety maintenance purpose.

[0007] In view of the shortcomings of existing technologies, in order to improve the closed-circuit system of the CDQ furnace air inlet system and the coke discharge system, improve the safety and reliability of operations during maintenance, prevent major safety accidents and ensure the safety and reliability of equipment during maintenance. Summary of the invention

[0008] In view of this, the present invention provides a CDQ furnace air inlet closed circuit system:

[0009] A closed-circuit air inlet system for a dry quenching furnace, the closed-circuit air inlet system for the dry quenching furnace comprising a primary dust removal unit and a boiler connected with a furnace body, the furnace body being divided into a pre-storage section and a cooling section from top to bottom, the furnace body forming an upper annular air duct at a position corresponding to the pre-storage section and the cooling section, a coke discharge system and a circulating air inlet system are arranged at the bottom of the dry quenching furnace, the circulating air inlet system comprising a circulating fan, an upper air chamber connecting pipe, a lower air chamber connecting pipe, an upper air chamber and a lower air chamber, the upper air chamber and the lower air chamber being connected with the furnace body, a flap valve being arranged at the outlet of the circulating fan, the flap valve being connected to the upper air chamber and the lower air chamber respectively through the upper air chamber connecting pipe and the lower air chamber connecting pipe, the circulating air flow in the furnace body enters the cooling section through the upper air chamber and the lower air chamber and flows back to the circulating fan through the upper annular air duct, the primary dust removal unit and the boiler; a flat gate is arranged on the coke discharge system, and a circulating air cut-off valve is arranged at the outlet between the circulating fan and the flap valve; a discharge cut-off valve is arranged below the flat gate.

[0010] Preferably, the circulating air shut-off valve is arranged between the circulating fan and the flap valve, and the circulating air shut-off valve is a fully enclosed flap valve.

[0011] Preferably, the discharge shut-off valve includes a chute body, a blind flange, and an inspection blind plate. The chute body includes an upper chute, a guide chute, and a lower chute. The guide chute is connected between the upper chute and the lower chute. A guide frame or the inspection blind plate is provided in the guide chute. Guide chute flanges are provided on both sides of the guide chute, and a blind flange is provided outside the guide chute flange.

[0012] Preferably, the inspection blind plate is provided with a sealing groove, a sealing strip is provided in the sealing groove, the guide groove has a sealing surface, and the sealing strip seals and connects the inspection blind plate and the sealing surface.

[0013] Preferably, a locking bolt is installed on the guide groove, and the locking bolt presses the inspection blind plate so that the sealing strip is in close contact with the sealing surface, and the inspection blind plate cuts off the passage between the upper chute and the lower chute.

[0014] Preferably, the coke discharge system is further provided with a vibrating feeder, a rotary sealing valve, a double-branch chute and a coke transport belt, and the discharge shut-off valve is installed at a position between below the flat gate and above the vibrating feeder.

[0015] Preferably, a channel is provided in the guide frame to connect the upper chute and the lower chute.

[0016] Preferably, the upper cone opening of the lower chute is larger than the lower cone opening of the upper chute.

[0017] The beneficial effect of the present invention is that the CDQ furnace is provided with an air inlet closed circuit system to form a sealed air circulation system, which can effectively prevent the leakage of coke powder. At the same time, a closed circuit system can be formed during maintenance to prevent the leakage of high-temperature coke powder and burn the staff, and the safety is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of a circulating air intake system and a coke discharge system of a CDQ furnace in the prior art;

[0020] Figure 2 It is a schematic diagram of a coke discharge system of a dry quenching furnace in the prior art;

[0021] Figure 3 It is a schematic diagram of the arrangement of a flat gate, a chute and a vibrating feeder in a coke discharge system of a dry quenching furnace in the prior art when coke discharge is stopped;

[0022] Figure 4 It is a schematic diagram of the arrangement of a flat gate, a chute and a vibrating feeder in a coke discharge system of a dry quenching furnace in the prior art during normal coke discharge;

[0023] Figure 5 It is a three-dimensional schematic diagram of a flat gate and a chute in a coke discharge system of a dry quenching furnace in the prior art;

[0024] Figure 6 Schematic diagram of the air inlet closed circuit system of the CDQ furnace of the present invention;

[0025] Figure 7 It is a schematic diagram of the arrangement of a flat gate, a discharge cut-off valve and a vibrating feeder in a discharge system when coke discharge is stopped in a closed air inlet system of a dry quenching furnace of the present invention;

[0026] Figure 8 It is a schematic diagram of the arrangement of a flat gate, a discharge cut-off valve and a vibrating feeder in a discharge system during normal coke discharge in a closed air inlet system of a dry quenching furnace of the present invention;

[0027] Fig. 9 It is a three-dimensional schematic diagram of the flat gate and the discharge cut-off valve in the air inlet closed-circuit system of the CDQ furnace of the present invention when they are cut off;

[0028] Fig.10 It is a three-dimensional schematic diagram of the flat gate and the discharge cut-off valve in the air inlet closed-circuit system of the CDQ furnace of the present invention when they are opened;

[0029] Fig.11 This is a side view of the discharge shut-off valve being opened;

[0030] Fig.12 yes Fig.11 AA section view when the discharge shut-off valve is shut off;

[0031] Fig.13 yes Fig.11 AA section view when the discharge shut-off valve is open;

[0032] Fig.14 It is a three-dimensional diagram of the circulating air shut-off valve.

[0033] Description of reference numerals:

[0034] 1. Circulating air outlet pipe, 2. Circulating air shut-off valve, 3. Flap valve, 4. Upper air chamber connecting pipe, 5. Lower air chamber connecting pipe, 6. Circulating air intake system, 7. Coke discharge system, 8. Flat gate, 9. Discharge shut-off valve, 10. Vibrating feeder, 11. Rotary sealing valve, 12. Double-branch chute, 13. Coke transport belt, 14. Transition chute, 15. CDQ furnace outlet, 16. Cross beam, 17. Lower air chamber, 18. Lower cone bucket, 19. Upper air chamber, 20. Lower annular air duct, 21. Upper cone bucket, 22. Wind cap, 23. Cooling section , 24, upper annular air duct, 25, pre-storage chamber, 26, dry quenching furnace mouth, 27, red coke, 28, primary dust removal, 29, boiler, 30, connecting pipe, 31, circulating fan, 901, chute body, 902, blind flange, 903, upper chute, 904, guide groove, 905, lower chute, 906, locking bolt, 907, maintenance blind plate, 908, sealing groove, 909, sealing strip, 910, sealing surface, 911, guide frame, 912, inner channel, 913, guide groove flange, 914, lower cone mouth, 915, upper cone mouth DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The present invention will be further described below in conjunction with the accompanying drawings.

[0037] The present invention provides the following technical solutions:

[0038] As attached Figures 6 to 14As shown, it is a preferred embodiment of the closed-circuit air inlet system of the dry quenching furnace of the present invention, the closed-circuit air inlet system of the dry quenching furnace comprises a primary dust removal unit 28, a boiler 29, a circulating air inlet system 6, and a coke discharge system 7 connected to the furnace body. The furnace body is divided into a pre-storage section 25 and a cooling section 23 from top to bottom. The furnace body forms an upper annular air duct 24 at a position corresponding to the pre-storage section 25 and the cooling section 23. The coke discharge system 7 and the circulating air inlet system 6 are provided at the bottom of the dry quenching furnace. The circulating air inlet system 6 comprises a circulating fan 31, an upper air chamber connecting pipe 4, a lower air chamber connecting pipe 5, an upper air chamber 19 and a lower air chamber 17. The upper air chamber 19 and the lower air chamber 17 are connected to the furnace body. A flap valve 3 is provided at the outlet of the circulating fan 31 to In order to adjust the air volume of the upper air chamber 19 and the lower air chamber 17, the flap valve 3 is connected to the upper air chamber 19 and the lower air chamber 17 through the upper air chamber connecting pipe 4 and the lower air chamber connecting pipe 5 respectively. The circulating air flow in the furnace body enters the cooling section 23 through the upper air chamber 19 and the lower air chamber 17 for heat exchange, and the high-temperature gas passes through the upper annular air duct 24 and the primary dust removal unit 28 and then passes through the boiler 29 for heat exchange and then flows back to the circulating fan 31; the coke discharge system 7 is provided with a flat gate 8, a vibrating feeder 10, a rotary sealing valve 11, a double-branch chute 12 and then passes through the coke transport belt 13, and is characterized in that: the circulating air intake system 7 is provided with a circulating air shut-off valve 2 at the outlet of the circulating fan 31; a discharge shut-off valve 9 is provided below the flat gate 8.

[0039] Specifically, the circulating air shut-off valve 2 is arranged between the circulating fan 31 and the flap valve 3. The circulating air shut-off valve 2 is a fully enclosed plug valve, and may also adopt a flap check valve structure or a flue plug valve structure. It only needs to be tight when closed.

[0040] like Figures 12-14 As shown, the discharge shut-off valve 9 includes a chute body 901, a blind flange 902, and an inspection blind plate 907. The chute body 901 includes an upper chute 903, a guide groove 904, and a lower chute 905. The guide groove 904 is connected between the upper chute 903 and the lower chute 905. A guide frame 911 or the inspection blind plate 907 is arranged in the guide groove 904. Guide groove flanges 913 are arranged on both sides of the guide groove 904. The guide groove flange 913 is provided with a blind flange 902 outside.

[0041] When maintenance is required, the blind flange 902 is removed, the maintenance blind plate 907 is inserted into the guide groove 904, and the blind flange 902 is installed on the outside of the guide groove flange 913; when normal operation is required after the maintenance is completed, the blind flange 902 is removed, the maintenance blind plate 907 is taken out, and replaced with the guide frame 911 to be inserted into the guide groove 904, and the blind flange 902 is installed on the outside of the guide groove flange 913; the guide groove 904 may not be installed with the guide frame 911, but the purpose of installing the guide frame 911 is to prevent coke from staying in the guide groove 904, which is not conducive to the next replacement.

[0042] Specifically, Fig.13 , 14 As shown, the inspection blind plate 907 is provided with a sealing groove 908, a sealing strip 909 is provided in the sealing groove 908, the guide groove 904 has a sealing surface 910, and the sealing strip 909 seals and connects the inspection blind plate 907 and the sealing surface 910. The sealing surface 910 in this embodiment refers to the top inner wall of the guide groove 904. Specifically, the sealing groove 908 is arranged around the top of the inspection blind plate 907. In the drawings of this embodiment, the sealing groove is formed on the top surface of the inspection blind plate 907. A locking bolt 906 is installed on the guide groove 904, and the locking bolt 906 presses the bottom surface of the inspection blind plate 907 so that the sealing strip 909 is in close contact with the sealing surface 910.

[0043] The guide groove 904 is provided with a locking bolt 906. When performing maintenance, the inspection blind plate 907 is inserted into the guide groove 904, and the locking bolt 906 is turned by a wrench. The locking bolt 906 presses the inspection blind plate 907 so that the sealing strip 909 is in close contact with the sealing surface 910, and the inspection blind plate 907 cuts off the passage between the upper chute 903 and the lower chute 905.

[0044] A flat gate 8 is arranged between the coke discharge system 7 and the CDQ furnace outlet 15. The coke discharge system is also provided with a vibrating feeder 10, a rotary sealing valve 11, a double-branched chute 12 and a coke transport belt 13. In the prior art, a transition chute 14 is originally arranged below the flat gate 8. In this embodiment, the transition chute 14 is cancelled and replaced by a discharge cut-off valve 9. The discharge cut-off valve 9 is installed at a position between the bottom of the flat gate 8 and the top of the vibrating feeder 10. The present invention forms an air intake closed-circuit system in the CDQ furnace by arranging the discharge cut-off valve 9 and the circulating air cut-off valve 2.

[0045] The guide frame 911 is provided with a channel 912 in communication with the upper chute 903 and the lower chute 905 , and the inner wall of the guide frame 911 may be provided with a wear-resistant lining.

[0046] like Fig.14 As shown, the upper cone opening 915 of the lower chute 905 is larger than the lower cone opening 914 of the upper chute 903 . This arrangement can effectively prevent coke from entering the guide chute 904 and reduce the wear of the lower chute 905 by coke.

[0047] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A closed-circuit air inlet system for a dry quenching furnace, the closed-circuit air inlet system for the dry quenching furnace comprising a primary dust removal unit (28) and a boiler (29) connected to a furnace body, the furnace body being divided into a pre-storage section (25) and a cooling section (23) from top to bottom, the furnace body forming an upper annular air duct (24) at a position corresponding to the pre-storage section (25) and the cooling section (23), a coke discharge system (7) and a circulating air inlet system (6) being provided at the bottom of the dry quenching furnace, the circulating air inlet system (6) comprising a circulating fan (31), an upper air chamber connecting pipe (4), a lower air chamber connecting pipe (5), an upper air chamber (19) and a lower air chamber (1 7), the upper air chamber (19) and the lower air chamber (17) are connected to the furnace body, and a flap valve (3) is arranged at the outlet of the circulation fan (31), and the flap valve (3) is connected to the upper air chamber (19) and the lower air chamber (17) through the upper air chamber connecting pipe (4) and the lower air chamber connecting pipe (5), respectively. The circulating air flow in the furnace body enters the cooling section (23) through the upper air chamber (19) and the lower air chamber (17) and flows back to the circulation fan (31) through the upper annular air duct (24), the primary dust removal unit (28), and the boiler (29); the coke discharge system (7) is provided with a flat gate (8), characterized in that: The circulating air intake system (7) is provided with a circulating air shut-off valve (2) at the outlet of the circulating fan (31); a discharge shut-off valve (9) is provided below the flat gate (8); the discharge shut-off valve (9) comprises a chute body (901), a blind flange (902), and a maintenance blind plate (907); the chute body (901) comprises an upper chute (903), a guide groove (904), and a lower chute (905); the guide groove (904) is connected between the upper chute (903) and the lower chute (905); the guide groove (904) is connected between the upper chute (903) and the lower chute (905); 04) is provided with a guide frame (911) or the inspection blind plate (907), guide groove flanges (913) are provided on both sides of the guide groove (904), a blind flange (902) is provided on the outside of the guide groove flange (913), the inspection blind plate (907) is provided with a sealing groove (908), a sealing strip (909) is provided in the sealing groove (908), the guide groove (904) has a sealing surface (910), and the sealing strip (909) seals and connects the inspection blind plate (907) and the sealing surface (910).

2. The CDQ furnace air inlet closed circuit system according to claim 1 is characterized by: The circulating air shut-off valve (2) is arranged between the circulating air fan (31) and the flap valve (3), and the circulating air shut-off valve (2) is a fully enclosed flap valve.

3. The CDQ furnace air inlet closed circuit system according to claim 1 is characterized by: A locking bolt (906) is installed on the guide groove (904), and the locking bolt (906) presses the inspection blind plate (907) so that the sealing strip (909) is in close contact with the sealing surface (910), and the inspection blind plate (907) cuts off the passage between the upper chute (903) and the lower chute (905).

4. The CDQ furnace air inlet closed circuit system according to claim 1 is characterized in that: The coke discharge system (7) is further provided with a vibrating feeder (10), a rotary sealing valve (11), a double-branch chute (12) and a coke transport belt (13), and the discharge shut-off valve (9) is installed at a position between below the flat gate (8) and above the vibrating feeder (10).

5. The CDQ furnace air inlet closed circuit system according to claim 1 is characterized by: The guide frame (911) is provided with a channel (912) communicating the upper chute (903) and the lower chute (905).

6. The CDQ furnace air inlet closed circuit system according to claim 1 is characterized by: The upper cone opening (915) of the lower chute (905) is larger than the lower cone opening (914) of the upper chute (903).

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